Bonuses and commissions
All bonuses and commissions paid to employees are liable for payroll tax.
If you pay a bonus that does not relate to any particular month, the payment will be considered to be for services performed in the month when it is paid.
For example, if you make the payment in June, it will be considered to be for services performed in June.
Commissions include all payments based on sales and are liable even if they are the only payments received by an employee.